A pressure-sensing technology generally provides a display screen with a pressure-sensing device, which will bring different interaction effects depending on slight or heavy touches on the touch screen by a finger. Different levels of pressure such as a slight pressing, a normal touching, and a heavy pressing etc., can be sensed by the screen, thereby achieving more varieties of operation modes.
Normally, the semiconductor pressure-sensing device provides a larger pressure-sensitive coefficient than the normal metallic pressure-sensing device, that is, the sensitivity of the semiconductor pressure-sensing device is higher than that of the metallic pressure-sensing device. FIG. 1 a schematic structural diagram of a semiconductor pressure-sensing touch device in a prior art. As shown in FIG. 1, the semiconductor pressure-sensing touch device includes a first pressure-sensitive resistor R1, a second pressure-sensitive resistor R2, a third pressure-sensitive resistor R3 and a fourth pressure-sensitive resistor R4, which form an electric bridge structure.
A first end a1 of the first pressure-sensitive resistor R1 and a first end a2 of the second pressure-sensitive resistor R2 are electrically connected to a first power inputting terminal Vcc, a second end b1 of the first pressure-sensitive resistor R1 and a first end a4 of the fourth pressure-sensitive resistor R4 are electrically connected to a first sense signal measuring terminal V+, a second end b4 of the fourth pressure-sensitive resistor R4 and a second end b3 of the third pressure-sensitive resistor R3 are electrically connected to a second power inputting terminal (e.g. GND terminal), a second end b2 of the second pressure-sensitive resistor R2 and a first end a3 of the third pressure-sensitive resistor R3 are electrically connected to a second sense signal measuring terminal V−. The semiconductor pressure-sensing touch device shown in FIG. 1 may be equivalent to a Wheatstone-bridge structure, the first pressure-sensitive resistor R1, the second pressure-sensitive resistor R2, the third pressure-sensitive resistor R3 and the fourth pressure-sensitive resistor R4 are connected to form a quadrangle ABCD which is called as four arms of the bridge. A diagonal line BD of the quadrangle ABCD is connected with a galvanometer G, and the two poles of the galvanometer G are, the first sense signal measuring terminal V+ and a second sense signal measuring terminal V−, respectively, a diagonal line AC of the quadrangle ABCD is connected to the first power inputting terminal Vcc and the second power inputting terminal GND. When a difference occurs between the voltages on the first power inputting terminal Vcc and the second power inputting terminal GND, the current flows through each branch of the bridge. When the resistance of the first pressure-sensitive resistor R1, the second pressure-sensitive resistor R2, the third pressure-sensitive resistor R3 and the fourth pressure-sensitive resistor R4 satisfies
                    R        1                    R        4              =                  R        2                    R        3              ,the potential of point B is equal to that of point D, and hence the current which flows through the galvanometer G is zero and the pointer of the galvanometer G points to a zero, thereby enabling the bridge in a balance state and
            R      1              R      4        =            R      2              R      3      is also called as a balance condition. When the resistance of the first pressure-sensitive resistor R1, the second pressure-sensitive resistor R2, the third pressure-sensitive resistor R3 and the fourth pressure-sensitive resistor R4 is not satisfied with above balance condition, the potential of point B is not equal to that of point D, and the current which flows through the galvanometer G is not zero, and the pointer of the galvanometer G deflects and the corresponding signal value is outputted, so that the pressure value may be determined.
The semiconductor pressure-sensing touch device is generally made in a laser crystallization scanning manner. Referring to FIG. 1, the laser crystallization scanning direction is parallel to the long side direction of the first pressure-sensitive resistor R1, and is perpendicular to the long side direction of the second pressure-sensitive resistor R2. Since the direction of the current which flows through the first pressure-sensitive resistor R1 and the second pressure-sensitive resistor R2 is different from the laser crystallization scanning direction, a slight difference in the resistances of the first pressure-sensitive resistor R1, the second pressure-sensitive resistor R2, the third pressure-sensitive resistor R3 and the fourth pressure-sensitive resistor R4 would occur, so that the balance condition
            R      1              R      4        =            R      2              R      3      of the bridge may not be satisfied. That is, when the pressure touch is not operated,
                    R        1                    R        4              ≠                  R        2                    R        3              ,so that the accuracy of the touch pressure detection is decreased.